A gas turbine engine includes a turbomachinery core having a high pressure compressor, combustor, and high pressure turbine (“HPT”) in serial flow relationship. The core is operable in a known manner to generate a primary gas flow. The high pressure turbine includes annular arrays (“rows”) of stationary vanes or nozzles that direct the gases exiting the combustor into rotating blades or buckets. Collectively one row of nozzles and one row of blades make up a “stage.” Typically two or more stages are used in serial flow relationship. These components operate in an extremely high temperature environment and, thus, must often be cooled by air flow to ensure adequate service life.
Due to the operating temperatures within the gas turbine engine, it is desirable to utilize materials with low coefficients of thermal expansion. For example, to operate effectively in such strenuous temperature and pressure conditions, composite materials have been developed, such as ceramic matrix composite (CMC) materials. CMC materials provide both temperature and density advantages over metallic materials, thereby making the materials desirable options for manufacturing high temperature, hot gas path components. However, CMC materials also have unique mechanical properties that must be considered during the design and application of such materials within the interior of a gas turbine engine. For example, CMC materials have relatively low tensile ductility or low strain to failure as compared to metallic materials. As a result, CMC-based components are often not equipped to handle significant mechanical loading during operation of the gas turbine engine.
In this regard, attempts have been made to form nozzle vanes from CMC materials to increase the high temperature capabilities of such components. However, these prior attempts have not fully addressed the mechanical loading issues for the nozzle vanes, thereby leading to durability challenges for the CMC-based components.
Accordingly, an improved nozzle segment assembly that provides increased mechanical support for CMC-based nozzle vanes would be welcomed in the technology.